Q: Late 2011 15" Macbook Pro running 10.9.5 crash then reboot

Aloha everyone,     
     Got a late 2011 Macbook Pro running 10.9.5

Running into a problem where it will seemingly crash. Black screen, but fan is running still. Then I'll have to force it to shut down my holding down the power button. Then upon trying to reboot, it'll fail about 3-4 times. Booting up to a black screen, hearing the "scratch", and the indicator light on the front illuminates. Then after a few tries it'll boot up like normal and then repeat the process over again.

any ideas on what could be causing this?

Mahalo!